Siemens Chief Makes His Mark With $1.32 Billion Energy Deal

German Conglomerate Also Streamlines Management

BERLIN—Siemens AG Chief Executive Joe Kaeser put his mark on the company he took over in August, making management changes, streamlining the conglomerate's structure and forging a billion-dollar deal to expand Siemens's energy business.

The German industrial company will buy most of Rolls-Royce Holdings PLC's civil energy operations, pushing Siemens further into a segment that already dominates its business. Siemens will pay £785...